Question

What is the density of jet fuel if the specific gravity is \(0.775 ?\)

Short answer

The density of jet fuel is 775 kg/m³.

Step-by-step solution

Understanding the Concept

Density is the mass per unit volume of a substance. Specific gravity is a dimensionless quantity that represents the ratio of the density of a substance to the density of a reference substance, usually water at 4 degrees Celsius. Since the density of water is approximately \(1000\,\text{kg/m}^{3}\), specific gravity can be used to find the density of another substance.

Formula for Density Using Specific Gravity

The formula that relates specific gravity \(SG\) to the density \(\rho\) of a substance is given by:\[ \rho = SG \times \text{Density of Water} \] Given that the density of water is \(1000\,\text{kg/m}^{3}\), we can use this formula to calculate the density of jet fuel.

Substitute the Values

Substitute the specific gravity given (\(0.775\)) and the known density of water (\(1000\,\text{kg/m}^{3}\)) into the formula:\[ \rho = 0.775 \times 1000\,\text{kg/m}^{3} \]

Calculate the Density

Perform the multiplication to find the density of the jet fuel:\[ \rho = 775\,\text{kg/m}^{3} \] This result tells us the density of jet fuel.

Key concepts

Specific Gravity

Specific gravity (SG) might sound complex, but it's actually a very simple concept. Imagine that you want to compare the density of any substance to that of water. Specific gravity is exactly that—a ratio. It's the density of a substance divided by the density of water.

• This means specific gravity is a dimensionless number—no units attached.
• It gives you a quick understanding of whether a substance is heavier or lighter than water.

When we say a substance has a specific gravity of 0.775, it tells us a lot: - The substance is less dense than water. - It’s lighter and will float on water.
Specific gravity is a useful tool in various fields, especially when you want quick insights into the properties of a material but don't want to measure its density directly.

Density of Water

Water is the universal standard for density comparisons. At 4 degrees Celsius, water reaches its maximum density at approximately \(1000 \, \text{kg/m}^{3}\).

• This number is crucial because it's the yardstick used for calculating specific gravity.
• Most liquids—and even solids—are compared to water to determine their specific gravity.

Furthermore, since the density of water is well-known and stable under certain conditions, it forms a reliable base for calculations. If you know the specific gravity of a material, you can quickly derive its density by multiplying the specific gravity by the density of water. This simple multiplication provides an easy transition from a dimensionless measure (specific gravity) to a meaningful metric (density).

Jet Fuel Density Calculation

Calculating the density of a substance like jet fuel involves a few straightforward steps once you understand how specific gravity works. Suppose you know the specific gravity of jet fuel is 0.775. Working with the standard density of water, you can find the density of the fuel:

• Use the formula: \( \rho = SG \times \text{Density of Water} \)
• Plug in the known specific gravity (0.775) and the density of water (\(1000 \, \text{kg/m}^{3}\))
• The calculation becomes: \( \rho = 0.775 \times 1000 \, \text{kg/m}^{3} = 775 \, \text{kg/m}^{3} \)

Using this calculation method, anyone can efficiently determine the density of jet fuel—or any other substance with a known specific gravity. Understanding this relation between specific gravity and density simplifies many real-world problems in science and engineering.